In 1939 Southeast Concrete Products was founded in the city of South Gate, California by Guy F. Mattox as a manufacturer of concrete products, including house foundations piers, stepping stones and incinerators (to burn trash).

In 1947 a partnership was founded by Guy F. Mattox and his son Robert. The location at that time was 222 South Atlantic Boulevard, Monterey Park, California. They manufactured steel "T" clothesline Poles, house foundation piers, stepping stones and incinerators.

In 1950 Robert became the sole owner of the Company. He purchased an acre of farm land in an area south of the city of El Monte, California (this area became South El Monte). The address was 11030 East Weaver Avenue.

In 1957 the manufacturing of concrete products was discontinued and the Company then expanded into the contracting field, Robert T Mattox holding a Masonry Contracting license and a General Contracting license.

In 1960 the Company relocated across the street to 11029 East Weaver Avenue, South El Monte, California.

In 1973 the Company was incorporated using the Corporate name of Southeast Construction Products, Inc.They continued to operate as a D. B. A. Southeast Concrete Products.

In 1973 the Company acquired the Covina Location at 19650 Arrow Highway, Covina, California. (Formerly Arrow Building Materials.)

In 1974 the Company acquired the Monrovia Location at 1239 S. Myrtle Avenue, Monrovia, California. At that time they discontinued Contracting and focused only on the building materials part of the business.

In 1983 the Corporation established an ESOP (Employees Stock Ownership Plan.) Over 90% of the Company Stock is now owned by the ESOP. They discontinued operating under the D.B.A. Southeast Concrete Products.

On April 14, 1997, the Corporation opened their 4th yard at 16514 E. Whittier Boulevard in the city of Whittier, California. (this was the former location of Brandels Building Materials).

On April 1, 2000, the Corporation opened their 5th yard at 3990 Riverside Drive in Chino, California. The property had been used as a building materials for over 47 years. (Formerly "Chino Valley Building Materials"). A modern steel fabricating shop has been set up at this location to supply the small and large contractor. The inventory of natural stone and elaborate displays of natural and imitation stone at this yard has quickly drawn designers and contractors alike to this yard when jobs are just in the planning stage.

January 3, 2006, the Corporation opened their 6th yard in the "Lake Elsinore Area" ay 33600 Mission Trail, Wildomar, California.

June 15, 2012, the Corporation closed the Wildomar, California location. (Their 6th yard.)

March 9th, 2015 Robert T. Mattox, Sr. Passed and left Southeast Construction Products, Inc. to the Employees making the company 100% employee owned.

The Qualified outside sales people and the sales people at all 5 offices are experienced and trained to help their customers select the proper materials and figure the quantities needed for their job. The Company's strongest asset is the "employee owners" that have grown-up in the business with practical "hands-on" experience. Products are purchased from all areas off the U.S. and some Foreign Countries. Southeast is attracting builders of Industrial & Commercial Buildings and Custom Homes, who rely on them to be their main supplier of products like slate, marble,brick, and stone.

Many other custom items that are required for these homes are also provided by Southeast. New product manufacturer representatives seek out Southeast to be a distributor of their products. Southeast is an exclusive distributor of many products that are being specified on plans being drawn up by architects for future construction projects in Southern California and other areas of the Country.

 As one of Southern California's largest building materials dealers/distributors, with over 100 trucks, trailers, forklifts, loaders, and the fabrication and manufacturing facility, Southeast is providing its customer's with the best service possible. "Over 75 Years" serving the Builders, Contractors and the Public and growing to accommodate their demands, shows a track record of stability and is an indiction of better things to come.